Who has used washing soda for buffer?

[reefburnaby]

Brad,

As an experiment, I would try turning off the skimmer for a day or two. The pH can either drop or rise. It can drop if there is too much CO2 in the water and the skimmer is aerating the CO2 out of the water. Or it can rise because CO2 from the room air is being injected in to the water via the skimmer.

The other thing I would check is that the CO2 bottle/regulator/everything else is not leaking. The good old soap bubble test should work in this situation.

Hope that helps.

- Victor.